A highly efficient catalyst indium (III) tribromide is used to synthesize 5-alkoxy-carbonyl-4-hydrocarbyl-3,4-dihydropyrimidin-2(1H)-ones by a three-component coupling of beta-keto ester, aldehydes and urea through im...A highly efficient catalyst indium (III) tribromide is used to synthesize 5-alkoxy-carbonyl-4-hydrocarbyl-3,4-dihydropyrimidin-2(1H)-ones by a three-component coupling of beta-keto ester, aldehydes and urea through improved Biginelli reaction.展开更多
{[K.18-Crown-6]Br3}n,a unique tribromide-type catalyst,was utilized for the N-boc protection of amines and trimethylsilylation(TMS)and tetrahydropyranylation(THP)of alcohols.The method is general for the preparation o...{[K.18-Crown-6]Br3}n,a unique tribromide-type catalyst,was utilized for the N-boc protection of amines and trimethylsilylation(TMS)and tetrahydropyranylation(THP)of alcohols.The method is general for the preparation of N-boc derivatives of aliphatic(acyclic and cyclic)and aromatic,and primary and secondary amines and also various TMS-ethers and THP-ethers.The simple separation of the catalyst from the product is one of the many advantages of this method.展开更多
A mild and efficient method for the conversion of alcohols to their corresponding methoxymethyl ethers and acetates using benzyltriphenylphosphonium tribromide （BTPTB） as catalyst is described. All reactions were pe...A mild and efficient method for the conversion of alcohols to their corresponding methoxymethyl ethers and acetates using benzyltriphenylphosphonium tribromide （BTPTB） as catalyst is described. All reactions were performed under completely heterogeneous reaction conditions in good to high yields.展开更多
A novel catalyst indium(Ⅲ) tribromide is shown to efficiently promote 5-carbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones from a three-component coupling of β-diketones, aldehydes and urea in ethanol. This modified on...A novel catalyst indium(Ⅲ) tribromide is shown to efficiently promote 5-carbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones from a three-component coupling of β-diketones, aldehydes and urea in ethanol. This modified one-pot Biginelli′s cyclocondensation not only features simple operation, but also takes place in nonpolluted environment. The structure of the Biginelli reaction product from β-diketones, salicylaldehyde and urea has been proposed to possess an oxygen-bridge.展开更多
Poly（4-vinylpyridinium tribromide） was prepared from poly（4-vinylpyridin） and used for the selective oxidation of a variety of sulfides to the corresponding sulfoxides. The oxidation reaction was carried out heter...Poly（4-vinylpyridinium tribromide） was prepared from poly（4-vinylpyridin） and used for the selective oxidation of a variety of sulfides to the corresponding sulfoxides. The oxidation reaction was carried out heterogeneously in acetone/water, as green solvent, at room temperature.展开更多
Study of the phase chemistry relation of quaternary system system CsBr-SmBr3-(13%)HBr-H2O at 25 ℃ is carried out in order to investigate the reaction of CsBr and SmBr3 in hydrobromic acid. A new compound 5CsBr.2SmBr3...Study of the phase chemistry relation of quaternary system system CsBr-SmBr3-(13%)HBr-H2O at 25 ℃ is carried out in order to investigate the reaction of CsBr and SmBr3 in hydrobromic acid. A new compound 5CsBr.2SmBr3.22H2O is discovered and obtained in the system. X-ray powder diffraction, thermal analysis (TG and DTA) and polarization character of the new compound obtained from the system are investigated.Meanwhile, the synthetic mechanisms of compounds (CsSm2Br7, Cs3Sm2Br9, Cs3SmBr6 and Cs2SmBr5) are suggested on the basis of phase chemical relation of the system.展开更多
Phase chemical relation of quaternary systems KBr-REBr3-HBr (13%)-H2O (25℃, RE=La, Sm) were determined, and the rule of phase change was also discovered bere when RE are light rare earth elements. It is found from th...Phase chemical relation of quaternary systems KBr-REBr3-HBr (13%)-H2O (25℃, RE=La, Sm) were determined, and the rule of phase change was also discovered bere when RE are light rare earth elements. It is found from the experiment that the quaternary systems in which KBr and REBr3 react in hydrobromic acid belong to a simple eutectic type,so the reaction mechanism for synthesizing compound K2REBr5 type and real action of the first step reaction can be explained with Meyer’s method. Furthermore, it can be seen from comparison between the systems in this paper and the system CsBr-REBr-HBr (13%)-H2O (25℃) that CsBr and REBr3 acting in hydrobromic acid with each other can form doublecompound easier than KBr and REBr3.展开更多
基金the National Natural Science Foundation of China(29872018&29972026).
文摘A highly efficient catalyst indium (III) tribromide is used to synthesize 5-alkoxy-carbonyl-4-hydrocarbyl-3,4-dihydropyrimidin-2(1H)-ones by a three-component coupling of beta-keto ester, aldehydes and urea through improved Biginelli reaction.
基金support for this work from the research affairs of Hamedan University of Medical Sciences,Hamedan,I.R.Iranpartial support of this work by the Research Affairs Office of Bu-Ali Sina UniversityCenter of Excellence in Development of Chemical Method(CEDCM)Hamedan,I.R.Iran
文摘{[K.18-Crown-6]Br3}n,a unique tribromide-type catalyst,was utilized for the N-boc protection of amines and trimethylsilylation(TMS)and tetrahydropyranylation(THP)of alcohols.The method is general for the preparation of N-boc derivatives of aliphatic(acyclic and cyclic)and aromatic,and primary and secondary amines and also various TMS-ethers and THP-ethers.The simple separation of the catalyst from the product is one of the many advantages of this method.
文摘A mild and efficient method for the conversion of alcohols to their corresponding methoxymethyl ethers and acetates using benzyltriphenylphosphonium tribromide （BTPTB） as catalyst is described. All reactions were performed under completely heterogeneous reaction conditions in good to high yields.
文摘A novel catalyst indium(Ⅲ) tribromide is shown to efficiently promote 5-carbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones from a three-component coupling of β-diketones, aldehydes and urea in ethanol. This modified one-pot Biginelli′s cyclocondensation not only features simple operation, but also takes place in nonpolluted environment. The structure of the Biginelli reaction product from β-diketones, salicylaldehyde and urea has been proposed to possess an oxygen-bridge.
基金Financial support for this work by the Ilam University,Ilam,Iran is gratefully acknowledged
文摘Poly（4-vinylpyridinium tribromide） was prepared from poly（4-vinylpyridin） and used for the selective oxidation of a variety of sulfides to the corresponding sulfoxides. The oxidation reaction was carried out heterogeneously in acetone/water, as green solvent, at room temperature.
文摘Study of the phase chemistry relation of quaternary system system CsBr-SmBr3-(13%)HBr-H2O at 25 ℃ is carried out in order to investigate the reaction of CsBr and SmBr3 in hydrobromic acid. A new compound 5CsBr.2SmBr3.22H2O is discovered and obtained in the system. X-ray powder diffraction, thermal analysis (TG and DTA) and polarization character of the new compound obtained from the system are investigated.Meanwhile, the synthetic mechanisms of compounds (CsSm2Br7, Cs3Sm2Br9, Cs3SmBr6 and Cs2SmBr5) are suggested on the basis of phase chemical relation of the system.
文摘Phase chemical relation of quaternary systems KBr-REBr3-HBr (13%)-H2O (25℃, RE=La, Sm) were determined, and the rule of phase change was also discovered bere when RE are light rare earth elements. It is found from the experiment that the quaternary systems in which KBr and REBr3 react in hydrobromic acid belong to a simple eutectic type,so the reaction mechanism for synthesizing compound K2REBr5 type and real action of the first step reaction can be explained with Meyer’s method. Furthermore, it can be seen from comparison between the systems in this paper and the system CsBr-REBr-HBr (13%)-H2O (25℃) that CsBr and REBr3 acting in hydrobromic acid with each other can form doublecompound easier than KBr and REBr3.
